This invention relates to multi-fiber fiber optic connectors.
Fiber optic connectors couple optical communication channels (e.g., optical fibers) to one or more optical devices (e.g., electro-optic and opto-electric devices). The optical communication channels may be defined by a bundle of glass or plastic fibers (a xe2x80x9cfiber optic cablexe2x80x9d), each of which is capable of transmitting data independently of the other fibers. Relative to traditional metal connections, optical fibers have a much greater bandwidth, they are less susceptible to interference, and they are much thinner and lighter. Because of these advantageous physical and data transmission properties, efforts have been made to integrate fiber optics into computer system designs. For example, in a local area network, fiber optics may be used to connect a plurality of local computers to centralized equipment, such as servers and printers. In this arrangement, each local computer has an optical transceiver for transmitting and receiving optical information. The optical transceiver may be mounted on a printed circuit board that supports one or more integrated circuits. Typically, each computer includes several printed circuit boards that are plugged into the sockets of a common backplane. The backplane may be active (i.e., it includes logic circuitry for performing computing functions) or it may be passive (i.e., it does not include any logic circuitry). An external network fiber optic cable may be connected to the optical transceiver through a fiber optic connector that is coupled to the backplane.
Other fiber optic applications have been proposed. For example, backplanes have been designed to interconnect the circuit boards of a computer system and thereby enable optical communication between the boards (see, e.g., U.S. Pat. Nos. 4,913,508, 5,134,679, and 5,793,919). These backplanes often are referred to as xe2x80x9coptical backplanes.xe2x80x9d Typically, an optical backplane includes one or more fiber optic cables that couple to connectors mounted on the edges of the printed circuit boards.
The invention features a flexible multi-fiber fiber optic connector that enables direct board-to-board optical communication but does not require data transmission through the backplane.
In one aspect, the invention features a multi-fiber fiber optic connector that includes a plurality of optical fibers terminating at proximal and distal ends, and a flexible support configured to hold the optical fibers in an elongated spaced-apart three-dimensional array. The support has a proximal end terminating at a proximal end face at which the proximal ends of the optical fibers terminate. The proximal end face of the support is sized and arranged to contact a port of an optical device whereupon one or more of the optical fibers couple to the optical device through the port.
As used herein, the term xe2x80x9coptical device portxe2x80x9d is intended to broadly refer to an interface where one or more optical fibers may optically couple to an optical device. This interface may include an optical lens, or it may include a portion of a light-sensing or light-transmitting surface of the optical device. Also, the term xe2x80x9coptical fibersxe2x80x9d is intended to refer to the material substance defining a single optical channel in the multi-fiber fiber optic connector. The optical channel may be defined by a single material (e.g., a single core material) or a composite material (e.g., a core material surrounded by an optical or non-optical material).
Furthermore, as used herein the language xe2x80x9cterminating atxe2x80x9d means terminating adjacent to or just beyond.
In another aspect, the invention features a multi-fiber fiber optic connector that includes a plurality of optical fibers formed from a core material with a refractive index. The optical fibers are embedded in an elongated integral support formed from a flexible cladding material with refractive index that is different from the refractive index of the core material. The support is configured to hold the optical fibers in a spaced-apart three-dimensional array characterized by insignificant optical coupling between the optical fibers.
Embodiments may include one or more of the following features.
The support preferably is configured to hold the optical fibers in a substantially parallel three-dimensional array. The optical fiber spacing along a particular line preferably is less than a characteristic dimension of the optical device port along the same line. The optical fiber spacing may be less than one-half of the characteristic dimension of the optical device port. The optical fiber spacing may be between about 10 xcexcm and about 250 xcexcm, and preferably is between about 50 xcexcm and about 125 xcexcm. The optical fiber spacing may be such that two or more optical fibers couple to the optical device upon contact between the proximal end face of the support and the optical device port.
The proximal end face of the support preferably is sized and arranged to overlay the optical device port. The proximal end face of the support may be sized to overlay two or more ports of a multi-port optical device (e.g., a transmitter and a receiver of an optical transceiver).
The optical fibers and the support preferably form a unitary flexible fiber optic cable. The optical fiber cores preferably are embedded in the cladding material of the support such that light injected into an optical fiber core travels through that core with insubstantial loss. The cladding material may include silicone.
The multi-fiber fiber optic connector may include a proximal terminal coupled to the proximal end of the support. The proximal terminal may be configured to position the proximal end face of the support against the optical device port. The proximal terminal may include a socket configured to receive a plug of the optical device, or a plug configured to be inserted into a socket of the optical device. The proximal terminal may be formed from a flexible material and may be sized and arranged to engage the optical device with a friction fit; the flexible terminal material may be formed integrally with the flexible support. The proximal terminal may include a biasing mechanism for urging the proximal end face of the support against the optical device port.
The support preferably includes a distal end face at which the distal ends of the optical fibers terminate. The distal end face may be sized and arranged to contact a port of a second optical device. The proximal and distal end faces of the support may be configured to optically couple one or more of the optical fibers to each of a pair of opposed optical devices coupled to facing sides of adjacent printed circuit boards connected to a common backplane.
Among the advantages of the invention are the following. The invention enables direct board-to-board optical communication without requiring data transmission through the backplane. Furthermore, the fiber spacing is such that at least one optical fiber couples to an optical device upon contact between the support end face and the optical device port. Thus, the inventive fiber optic connector may couple to an optical device without requiring complex and precise alignment mechanisms between the optical device and the fiber optic connector.
Other features and advantages of the invention will become apparent from the following description, including the drawings and the claims.